Subscriber networks deliver voice, data, and video to subscribers over a complex web of hubs, nodes, amplifiers, and passive devices. Fiber-based networks may utilize multiple splices to provide connectivity to subscribers. Network management practices typically include device numbering systems to facilitate network topographical management. Device numbering systems are hierarchical thereby mimicking the trunk/cascade structure of the network itself. A well-implemented numbering system provides information about the physical location of a particular device within a network and the other devices to which the particular device connects.
Device numbering systems are generally designed to identify a device within a network to a level within the network deemed useful for network management. That is, a numbering system is used to manage network traffic, schedule maintenance, identify available capacity, balance loads among devices, and other important tasks. However, such a device numbering system is not able to isolate network problems to a device or cascade level.
FIG. 1 illustrates a typical cable-based system architecture. A headend 100 communicates with hub 105. Hub 105 communicates with nodes 110A, 110B and 110C. Nodes 110 provide an interface between the fiber-based transport medium of the cable network (between the headend 100 and upstream side of nodes 110) and the coax-based medium (between the downstream side of nodes 110 and the subscriber interface 145). The downstream side of node 110B is further illustrated as connecting to amplifier 1 125 which in turn is connected to amplifier 2 130. The serial path from node 120B through amplifier 1 125 to amplifier 2 130 is referred to as a cascade relative to node 120B. Amplifier 1 125 has three branches that are cascades relative to amplifier 1 125 and sub-cascades relative to node 120B.
As will be appreciated by those skilled in the art, FIG. 1 is a greatly simplified schematic of a cable network architecture. A hub typically serves 20,000 subscribers. A typical hub may support 100 nodes with each node capable of serving 2000 subscribers. In order to maintain signal quality and quality of service commitments, trunk amplifiers maintain high signal quality. Internal bridger modules in the trunk amplifiers may be used to boost signals for delivery to subscribers' homes. Line Extender amplifiers maintain the high signal levels in cascade after the trunk amplifiers, through the neighborhoods. Taps divide out small amounts of signal for connection to the homes. A tap typically has 2, 4 or 8 ports for connection of drop cables. Nominal cascade limits are up to 4 trunk amplifiers followed by up to 3 line extenders, with more in very rural areas. In suburban areas, cascades typically comprise 2 trunk and 2 line extenders. Because branching is unlimited, the total device count per node may be large despite short cascades.
In addition, cable-based systems may have tap configurations that result in many ports emanating from a single cascade. Fiber-based systems may have multiple splices to provide connectivity to subscribers.
Because of the number of devices and branches in a subscriber network, identifying the cause of an outage can be a daunting problem. Subscriber network troubleshooting is often time consuming and craft/skill dependent in a sequence of staff positions. Customer service must interpret and correlate customer complaints, dispatch must efficiently contact and direct the maintenance crew, and the maintenance crew must efficiently troubleshoot a geographically dispersed system.